Power Conversion Apparatus and Control Method Thereof

This application is based on and claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2024-0199785, filed on Dec. 30, 2024, in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety.

The disclosure relates to a power conversion apparatus and a control method thereof, and more particularly, to a power conversion apparatus including a bipolar inverter having an interleaved structure, and a control method of the power conversion apparatus.

As the use of renewable energy sources, such as photovoltaic generation, expands, there is a growing need to improve the performance of grid-connected inverters built into energy storage systems (ESS) that support the use of renewable energy sources. In particular, to supply alternating current (AC) 120 V voltage used in places such as the United States and Japan, a method of connecting an autotransformer to a single-phase three-wire configuration is widely adopted. However, when using an autotransformer, there are disadvantages such as increased volume and increased cost, and therefore, a technological alternative is required to compensate for the above disadvantages.

To solve these problems, a split phase technique has been proposed, which has attracted attention as a method capable of enabling efficient voltage supply while replacing the autotransformer. A bipolar method, which is one of the common configurations of inverter topology using the split phase technique, has the advantages of simple control and low leakage current. However, when only the bipolar method is used, there are disadvantages in that an inductor volume increases due to high total harmonic distortion (THD) and switching frequency current ripple occurring in a grid-side inductor.

Accordingly, to maximize the performance of an ESS utilizing renewable energy, a new technological approach is needed that may overcome the limitations of the existing autotransformer-based configuration and a bipolar inverter in terms of performance and economic efficiency.

The background technology described above is technical information that the inventor possessed for deriving the disclosure or acquired in the process of deriving the disclosure, and cannot necessarily be considered as publicly known technology disclosed to the general public prior to the application for the disclosure.

The disclosure provides a power conversion apparatus and a method thereof. Objectives to be solved by the disclosure are not limited to the objectives mentioned above, and other objectives and advantages of the disclosure that are not mentioned may be understood through the following description, and will be more clearly understood through the embodiments of the disclosure. In addition, it will be appreciated that the objectives and advantages to be solved by the disclosure may be realized by the means and combinations thereof indicated in the patent claims.

As a technical means for achieving the above-described technical objectives, a first aspect of the disclosure may provide a power conversion apparatus including an input circuit generating an input voltage, a buck-boost converter connected to the input circuit, a first full-bridge inverter and a second full-bridge inverter, which are connected to the buck-boost converter, at least one first inductor connected to the first full-bridge inverter, at least one second inductor connected to the second full-bridge inverter, an output circuit connected to the at least one first inductor and the at least one second inductor to generate an alternating current output voltage, and at least one processor configured to apply a first carrier signal and a reference signal to the first full-bridge inverter and apply a second carrier signal and the reference signal to the second full-bridge inverter, wherein the first full-bridge inverter operates based on the first carrier signal and the reference signal, and the second full-bridge inverter operates based on the second carrier signal and the reference signal.

A second aspect of the disclosure may provide a power conversion method including applying a first carrier signal and a reference signal to a first full-bridge inverter, applying a second carrier signal and the reference signal to a second full-bridge inverter, and obtaining an alternating current output voltage corresponding to an input voltage as the first full-bridge inverter and the second full-bridge inverter operate, wherein first full-bridge inverter and the second full-bridge inverter are connected to a buck-boost converter, the buck-boost converter is connected to an input circuit that generates the input voltage, and an output circuit generating the alternating current output voltage is connected to at least one first inductor and at least one second inductor.

A third aspect of the disclosure may provide a computer-readable recording medium having recorded thereon a program to cause a computer to execute the method of the second aspect.

Other aspects, features, and advantages other than those described above will become apparent from the following drawings, claims, and detailed description of the disclosure.

Advantages and features of the disclosure and methods of achieving the same will be apparent with reference to embodiments and drawings described below in detail. The disclosure may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. The disclosure should be understood to include all transformations, equivalents, or substitutes included in the spirit and technical scope of the disclosure. The embodiments to be disclosed below are provided so that the disclosure will be complete and will fully convey the scope of the disclosure to those skilled in the art to which the disclosure pertains. In the description of the disclosure, if it is determined that a detailed description of a related known technology may obscure the gist of the disclosure, the detailed description is omitted.

The terms used in the application are used only to describe particular embodiments and are not intended to limit the disclosure. Singular expressions include plural expressions, unless the context clearly indicates otherwise. In the application, it should be understood that terms such as “include” or “have” are intended to specify the presence of a feature, number, step, operation, component, part, or combinations thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

Some embodiments of the disclosure may be represented by functional block configurations and various processing steps. Some or all of these functional blocks may be implemented with various numbers of hardware and/or software configurations that perform specific functions. For example, the functional blocks of the disclosure may be implemented by one or more microprocessors or by circuit configurations for a certain function. In addition, for example, the functional blocks of the disclosure may be implemented in various programming or scripting languages. Functional blocks may be implemented as algorithms that are executed by one or more processors. Also, the disclosure may employ conventional techniques for electronic environment setting, signal processing, and/or data processing. Terms such as “mechanism,” “element,” “means,” and “composition” may be used broadly and are not limited to mechanical and physical configurations.

In addition, connecting lines or connecting members between components depicted in the drawings are only illustrative of functional connections and/or physical or circuit connections. In an actual device, connections between components may be represented by a variety of alternative or additional functional, physical, or circuit connections.

Hereinafter, the disclosure will be described in detail with reference to the attached drawings.

1 FIG. is an example diagram for schematically describing a power supply system.

1 FIG. 10 11 12 14 15 10 16 Referring to, a power supply systemmay include a photovoltaic module, a device, a load, and/or distribution equipment. The power supply systemmay be connected to an external power grid.

11 11 At least one photovoltaic modulemay be installed on the roof or exterior wall of a building to generate power. A plurality of photovoltaic modulesmay be connected to form a photovoltaic module array.

11 12 12 11 12 11 12 10 11 The photovoltaic modulemay be connected to the device. For example, at least one devicemay be connected to each photovoltaic module. As an example, in case that one deviceis connected to each photovoltaic module, the number of devicesconfiguring the power supply systemmay be equal to the number of photovoltaic modules.

12 11 12 11 10 16 14 The devicemay be a power conditioning system (PCS) or power conversion system that performs power conversion for power generated from the photovoltaic module. For example, the devicemay perform a certain conversion on the power generated from the photovoltaic moduleand supply the converted power to other components of the power supply system(e.g., the power gridand/or the load, etc.).

12 12 In some embodiments, the devicemay be module-level power electronics (MLPE). For example, the devicemay be an optimizer or a micro-inverter (MI).

12 12 11 16 14 As an example, in case that the deviceis an optimizer, the devicemay regulate the power produced from the photovoltaic moduleand output the regulated power to an inverter (e.g., a string inverter). Current converted by an inverter (e.g., direct current converted into alternating current) may be output to the power gridor the load.

12 12 11 12 16 14 As another example, in case that the deviceis an MI, the devicemay convert power generated from the photovoltaic module(e.g., conversion of direct current into alternating current). The current converted by the devicemay be output to the power gridor the load.

10 13 12 15 13 12 13 15 When necessary, the power supply systemmay further include a combiner. At least some of the devicesmay be connected to the distribution equipmentvia the combiner. For example, power output from a plurality of devicesmay be combined into one output in the combinerand supplied to the distribution equipment.

12 15 13 12 15 13 12 15 13 For example, the deviceand the distribution equipmentmay also be connected by a power path that does not include the combiner, and at least one devicemay be connected to the distribution equipmentby a power path that does not include the combiner, and at least one other devicemay be connected to the distribution equipmentvia the combiner.

13 12 11 12 16 13 The combinermay perform control on the voltage, current, and/or power output from the deviceaccording to the power supply status of the photovoltaic module, the device, and/or the power grid, and may set an operating mode of the combinerto a diagnosis mode or an operation mode, etc.

13 13 13 13 11 12 16 13 In some embodiments, the combinermay include an energy management system (EMS) that controls an operation of the combiner. The EMS may perform control on the voltage, current, and/or power supplied to the combineror output from the combineraccording to the power supply status of the photovoltaic module, the deviceand/or the power grid, and may set the operating mode of the combinerto a diagnosis mode or an operation mode, etc.

14 11 17 16 14 The loadrefers to an object that is installed in an electric power consumer, such as a house, commercial facility, or factory, and operates by receiving at least one of energy generated by the photovoltaic module, energy stored in an energy storage device, and/or energy supplied from the power grid. For example, in case that the electric power consumer receiving power is a house, the loadmay include home appliances, such as a washing machine, a refrigerator, or a television (TV).

16 16 16 10 10 10 The power gridmay include an infrastructure system for generating, transmitting, and distributing power. For example, the power gridmay include infrastructure systems, such as power plants, substations, and power lines. For example, the power gridmay transmit electric energy generated by the power plant to the power supply systemor transmit surplus power generated by the power supply systemto the outside of the power supply system.

16 10 16 For example, commercial power transmitted from the power gridthrough a power pole may be supplied to an electric power consumer through a transformer. For example, the power supply systemmay also be implemented as an off-grid system that is not connected to the power grid.

10 17 10 17 17 11 16 17 14 14 For example, the power supply systemmay further include at least one energy storage device. When necessary, the power supply systemmay include a plurality of energy storage devices. The energy storage devicemay receive and store power generated by the photovoltaic moduleand/or power transmitted from the power grid. The energy storage devicemay efficiently supply power by storing the power and supplying the power to the loadwhen the loadneeds power.

17 The energy storage devicemay include a battery that stores power and a power conversion module. The battery may be provided with a battery management system (BMS) that monitors the state-of-charge (SOC), state-of-health (SOH), voltage and/or current of the battery, performs diagnostics on the battery, and performs safety functions such as current cutoff.

17 In some embodiments, the power conversion module may be a PCS that performs conversion between battery-side power and the opposite-side power. For example, the PCS may perform conversion between battery-side direct current and the opposite-side alternating current. As an example, the PCS may include a bidirectional direct current (DC)-DC converter that is connected to a battery and converts voltage, and a bidirectional inverter that connects the DC-DC converter to the outside of the energy storage device.

17 17 17 17 16 17 In some embodiments, the energy storage devicemay further include an EMS that controls an operation of the energy storage device. The EMS may perform control on the voltage, current, and/or power supplied to the energy storage deviceor output from the energy storage deviceaccording to the power supply status of the battery and/or the power grid, and may set the operating mode of the energy storage deviceto a diagnosis mode or an operation mode, etc.

10 10 13 17 13 17 When necessary, an EMS coupled to a certain component of the power supply systemmay not only control an operation of the certain component, but may also further control operations of other components of the power supply system. For example, an EMS coupled to the combineror an EMS coupled to the energy storage devicemay control both the operation of the combinerand the operation of the energy storage device.

15 10 10 15 11 14 15 12 11 11 14 15 17 16 For example, the distribution equipmentmay provide electrical connection between the components of the power supply systemand may control the power flow of the power supply system. For example, the distribution equipmentmay electrically connect the photovoltaic moduleto the load. As an example, the distribution equipmentmay be connected to the deviceconnected to the photovoltaic moduleto electrically connect the photovoltaic moduleto the load. When necessary, the distribution equipmentmay be further connected to at least one of the energy storage deviceand the power grid.

15 10 15 11 14 For example, the distribution equipmentmay be a distribution panel that distributes power within the power supply system. As an example, the distribution equipmentmay be a master service panel (MSP) that distributes power generated by the photovoltaic moduleto the loador the like.

15 10 12 As another example, the distribution equipmentmay be a main controller that performs power distribution within the power supply systemand controls each device. As an example, the main controller may include a switch, a circuit breaker, and a controller. The switch, the circuit breaker, and the controller may each be implemented as independent devices, or at least some of the switch, the circuit breaker, and the controller may be included in a single device.

12 14 12 17 10 The main controller may include a switch that controls electrical connections between components connected to the main controller, such as the deviceand the load. For example, the main controller may include a relay or power semiconductor that provides or blocks the electrical connection to the deviceand/or the energy storage devicedepending on an operating status of each component of the power supply system.

11 10 12 14 The main controller may perform a rapid shutdown to stop the power generation of the photovoltaic modulein an emergency situation such as an overcurrent occurrence within the power supply system. To this end, the main controller may include a circuit breaker that blocks the connection between the deviceand the load.

12 17 10 The main controller may include a controller that generally controls the operation of the main controller. In addition to the main controller, the controller may control the operations of other components (e.g., the deviceor the energy storage device) of the power supply system.

11 12 13 14 16 17 12 17 The controller may perform control on the voltage, current, and/or power output from each component or supplied to each component, according to the power supply status of the photovoltaic module, the device, the combiner, the load, the power gridand/or the energy storage device. In some embodiments, the controller may set the operating mode of the main controller, the device, and/or the energy storage deviceto a diagnostic mode or an operation mode, etc.

11 12 13 17 10 10 12 10 10 For example, the controller may control the photovoltaic module, the device, the combiner, and/or the energy storage device, based on the state of the power supply system. As an example, the controller may control other components of the power supply systemby allowing the main controller to communicate with other components (e.g., the deviceor the like) of the power supply system. Communication between the main controller and other components of the power supply systemmay be performed by using a power line communication (PLC) method, but is not limited thereto.

12 11 11 12 As an example, the controller may control the deviceaccording to the power generation status of the photovoltaic module. For example, the main controller may receive a control command from a server that monitors the power generation status of the photovoltaic module, and the controller may control the deviceaccording to the control command.

14 16 16 11 17 The main controller may supply power to at least some of the loadsin case that power supply from the power gridis not smooth (e.g., in an off-grid situation). For example, in case that the power supply from the power gridis not smooth, the main controller may preferentially supply power generated from the photovoltaic moduleand/or power stored in the energy storage deviceto a backup load having a relatively high need for a stable power supply.

10 15 11 17 For example, the power supply systemmay further include an auxiliary power generation device (e.g., a diesel generator, etc.) that generates power in a separate manner other than photovoltaic generation. For example, the auxiliary power generation device may be further connected to the distribution equipment. In case that the backup load cannot be coped with only the photovoltaic moduleand the energy storage devicedue to environmental factors such as time zone or weather, the main controller may supply power generated by the auxiliary power generation device to the backup load.

The controller may be implemented by at least one processor. A processor may process commands in a computer program by performing basic arithmetic, logic, and input/output operations. Here, the commands may be provided from an internal memory of the main controller or from an external device. In some embodiments, the processor may control the overall operation of other components included in the main controller.

For example, the processor may perform at least some of the data analysis, processing, and result information generation for performing the above-described operations by using at least one of a machine learning, neural network, or deep learning algorithm as a rule-based or artificial intelligence algorithm. Examples of neural networks may include neural network models based on architectures such as convolutional neural network (CNN), deep neural network (DNN), and recurrent neural network (RNN).

For example, the processor may also be implemented as an array of multiple logic gates, or may be implemented as a combination of a general-purpose microprocessor and a memory storing a program that may be executed on the microprocessor. For example, the processor may include a general-purpose processor, a central processing unit (CPU), a microprocessor, a digital signal processor (DSP), a controller, a microcontroller, a state machine, or the like.

In some environments, the processor may include an application-specific integrated circuit (ASIC), a programmable logic device (PLD), a field-programmable gate array (FPGA), or the like. For example, the processor may refer to a combination of processing devices, such as a combination of a DSP and a microprocessor, a combination of a plurality of microprocessors, a combination of one or more microprocessors coupled to a DSP core, or any combinations of such other configurations.

10 10 10 2 3 FIGS.and The power supply systemmay be implemented in various forms by combining at least some of the components described above. Hereinafter, various embodiments of the power supply systemare described with reference to. However, the implementation method of the power supply systemis not limited to the embodiments to be described below.

2 FIG. is an example of a power supply system according to an embodiment.

2 FIG. 30 31 32 33 34 35 30 36 Referring to, a power supply systemaccording to an embodiment may include a photovoltaic generation device, a combiner, a load, a distribution panel, and an energy storage device. In some embodiments, the power supply systemmay be connected to an external power grid.

35 34 35 32 In an embodiment, the energy storage devicemay be connected to the distribution paneland may be charged or discharged. In another embodiment, the energy storage devicemay be connected to the combinerand may be charged or discharged.

33 31 35 33 35 30 31 33 35 35 31 33 35 36 In case that the loadcannot be coped with only the photovoltaic generation device, power stored in the energy storage devicemay be used to cope with the loadby additionally providing the energy storage devicein the power supply system. In some embodiments, in case that power generated by the photovoltaic generation deviceexceeds an amount of power required to cope with the load, the excess amount may be stored in the energy storage device. For example, in case that a charge amount of the energy storage deviceis at a threshold or less and the power generated by the photovoltaic generation devicedoes not exceed the amount of power required to cope with the load, the energy storage devicemay be charged with power supplied from the power grid.

30 33 35 Accordingly, the power supply systemmay perform efficient power supply to the loadby using the energy storage device.

32 31 31 33 36 32 For example, the combinermay perform control on the voltage, current, and/or power output from the photovoltaic generation deviceaccording to the power supply status of the photovoltaic generation device, the load, and/or the power grid, and may set the operation mode of the combinerto a diagnosis mode or an operation mode, etc.

35 35 35 31 33 36 35 In some embodiments, the energy storage devicemay perform control on the voltage, current, and/or power supplied to the energy storage deviceor output from the energy storage device, according to the power supply status of the photovoltaic generation device, the load, and/or the power grid, and may set the operating mode of the energy storage deviceto a diagnosis mode or an operation mode, etc.

30 34 31 32 31 In an embodiment, the power supply systemmay further include a sub-panel (not shown) connected to the distribution panel. At this time, at least one photovoltaic generation devicemay be connected to the sub-panel through the combiner, and at least one other photovoltaic generation devicemay be directly connected to the sub-panel.

35 30 32 34 In some embodiments, at least one energy storage devicemay be integrated into the power supply systemby being connected to the combiner, the distribution panel, or the sub-panel.

31 34 32 31 34 32 31 34 32 For example, at least one photovoltaic generation deviceand the distribution panelmay be connected by a power path that does not include the combiner. For example, at least one photovoltaic generation devicemay be connected to the distribution panelvia a power path that does not include the combiner, and at least one other photovoltaic generation devicemay also be connected to the distribution panelvia the combiner.

31 32 31 In an embodiment, at least one photovoltaic generation devicemay be connected to the sub-panel via the combiner, and at least one other photovoltaic generation devicemay be connected directly to the sub-panel.

30 31 30 The power supply systemmay increase the total power generation amount of the photovoltaic generation devicethat may be integrated into the power supply systemby including the sub-panel that provides additional capacity.

3 FIG. is an example of a power supply system according to another embodiment.

3 FIG. 40 41 42 43 44 45 46 40 47 Referring to, a power supply systemaccording to an embodiment may include a photovoltaic generation device, a combiner, a load, a main controller, a distribution panel, and an energy storage device. In some embodiments, the power supply systemmay be connected to an external power grid.

41 42 43 46 31 32 33 35 44 3 FIG. 2 FIG. 3 FIG. 1 FIG. For example, the photovoltaic generation device, the combiner, the load, and the energy storage deviceillustrated inmay correspond to the photovoltaic generation device, the combiner, the load, or the energy storage deviceillustrated in, respectively. In some embodiments, the main controllerillustrated inmay correspond to the main controller described above with reference to.

42 41 44 42 41 44 The combinermay electrically connect at least one photovoltaic generation deviceto the main controller. For example, the combinermay combine power output from at least one photovoltaic generation deviceinto one output and supply the one output to the main controller.

44 42 45 47 44 46 44 42 45 46 47 44 47 45 46 44 46 45 The main controllermay electrically connect the combiner, the distribution panel, and the power gridto each other. In some embodiments, the main controllermay connect the above-described components to auxiliary power sources such as the energy storage deviceand/or an auxiliary power generation device (e.g., a diesel generator, etc.). For example, the main controllermay output power supplied from the combinerto the distribution panel, the energy storage device, and/or the power grid. In some embodiments, the main controllermay output power supplied from the power gridto the distribution panelor the energy storage device. In some embodiments, the main controllermay output power supplied from the energy storage deviceto the distribution panel.

45 44 43 40 41 43 45 The distribution panelmay electrically connect the main controllerto at least one load. Accordingly, the power supply systemmay supply power generated from the photovoltaic generation deviceto the loadthrough the distribution panel.

40 46 40 44 40 43 47 The power supply systemmay integrate a plurality of energy storage devicesand/or auxiliary power generation devices into the power supply systemby including the main controller, thereby stably supplying power. In some embodiments, the power supply systemmay stably supply power to the load, such as a backup load, even in an off-grid environment in which power is not stably supplied from the power grid.

44 41 43 46 47 44 41 46 For example, the main controllermay perform control on the voltage, current, and/or power output from each component or supplied to each component, according to the status of the photovoltaic generation device, the load, the energy storage device, and/or the power grid, and may set the operating mode of the main controller, the photovoltaic generation device, and/or the energy storage deviceto a diagnosis mode or an operation mode, etc.

40 44 45 43 43 45 In an embodiment, the power supply systemmay further include a sub-panel (not shown) that is connected to the main controllerand distinct from the distribution panel. At this time, at least one backup load having a relatively high need for stable power supply among the loadsmay be connected to the sub-panel, and at least one non-backup load having a relatively low need for stable power supply among the loadsmay be connected to the distribution panel.

44 42 45 46 47 44 42 46 47 45 The main controllermay electrically connect the combiner, the distribution panel, the energy storage device, the power grid, and the sub-panel to each other. The main controllermay supply power supplied from the combiner, the energy storage device, and/or the power gridto at least one non-backup load through the distribution paneland to a backup load through the sub-panel.

40 44 45 47 45 44 44 42 45 46 45 44 47 For example, in an embodiment, the power supply systemmay further include a sub-panel that is connected to the main controllerand distinct from the distribution panel, and the power gridmay be connected to the distribution panelinstead of being connected to the main controller. That is, the main controllermay electrically connect the combiner, the distribution panel, the energy storage device, and the sub-panel to each other, and the distribution panelmay electrically connect the main controller, the non-backup load, and the power gridto each other.

40 44 42 46 45 43 47 For example, the power supply systemmay be implemented by connecting the main controller, which connects the combinerto the energy storage device, to the distribution panelthat is pre-installed to connect at least one loadto the power grid.

40 43 47 Accordingly, the power supply systemmay stably supply power to the load, such as a backup load, even in an off-grid environment in which power is not stably supplied from the power grid.

4 FIG. 500 is a block diagram of a power conversion apparatusaccording to an embodiment.

4 FIG. 500 500 501 502 503 Referring to, the power conversion apparatus(hereinafter, referred to as a “device”) may include a memory, a processor, and a power conversion module.

500 12 17 500 35 46 4 FIG. 1 FIG. 2 FIG. 3 FIG. For example, the deviceofmay be included in the deviceor the energy storage deviceof. Furthermore, the devicemay be included in the energy storage deviceofor the energy storage deviceof.

501 500 502 503 The memoryis hardware that stores various types of data processed within the device, and may store a program for processing and controlling the processorand the power conversion module.

501 The memorymay include random access memory (RAM), such as dynamic random access memory (DRAM), and static random access memory (SRAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), compact disc (CD)-ROM, Blu-ray or other optical disk storage, hard disk drive (HDD), solid-state drive (SSD), or flash memory.

502 500 502 501 503 501 The processormay control the overall operation of the device. For example, the processormay control the memoryand the power conversion modulein general by executing programs stored in the memory.

502 500 503 500 501 502 500 503 500 The processormay control the operations of the deviceand the power conversion moduleincluded in the deviceby executing programs stored in the memory. The processormay control at least some of the operations of the deviceand the power conversion moduleincluded in the device.

502 The processoraccording to an embodiment may apply a first carrier signal and a reference signal to a first full-bridge inverter, and may apply a second carrier signal and the reference signal to a second full-bridge inverter.

5 FIG. The first full-bridge inverter may be a circuit implemented as a full-bridge inverter including a plurality of switches. Here, a switch may include a switching element. For example, each switch may further include a diode and a capacitor, which are connected in parallel to the switching element. The full-bridge inverter may have a full-bridge configuration, and circuit elements included in the full-bridge configuration and the connection relationship between respective elements will be described later with reference to.

A switching element may refer to an element that operates by repeatedly switching on and off states to convert power. The switching element may be, for example, a metal-oxide-semiconductor field-effect transistor (MOSFET), an insulated gate bipolar transistor (IGBT), or a bipolar junction transistor (BJT).

The first carrier signal is a signal applied in the form of a voltage and may be applied to the plurality of switches included in the first full-bridge inverter. The first carrier signal may be a voltage waveform having a constant cycle, for example, in the form of a triangle wave, a square wave, or a sine wave. The first carrier signal may be applied simultaneously with the reference signal being applied to the plurality of switches.

The second full-bridge inverter may have a circuit structure implemented as a full-bridge inverter including a plurality of switches and may be structurally identical to the first full-bridge inverter.

The second carrier signal is a signal applied in the form of a voltage, similar to the first carrier signal, and may be applied to the plurality of switches included in the second full-bridge inverter. The second carrier signal may be a voltage waveform having a constant cycle, for example, a triangular wave, a square wave, or a sine wave. The second carrier signal may be applied simultaneously with the reference signal being applied to the plurality of switches.

The reference signal is a signal applied in the form of a voltage and may be applied to the plurality of switches included in the first full-bridge inverter and the plurality of switches included in the second full-bridge inverter. The reference signal may be a voltage waveform having a constant cycle, for example, a sine wave, a triangular wave, or a square wave. The reference signal may operate as a gate signal for each of the plurality of switches.

502 The processoraccording to an embodiment may control a first switch and a second switch, based on the voltage difference between a first capacitor and a second capacitor.

The first capacitor and the second capacitor may each be a capacitor element. The voltage of the first capacitor and the voltage of the second capacitor may refer to voltages applied across both ends of each capacitor element.

7 FIG. The first switch and the second switch may each include a switching element, and may be the same element as the switch included in the full-bridge inverter described above. A third inductor may be an inductor element. The connection relationships of the first capacitor, the second capacitor, the first switch, the second switch, and the third inductor, and a circuit structure including the same are described below with reference to.

At this time, the first capacitor, the second capacitor, the first switch, the second switch, and the third inductor may all be elements included in a buck-boost converter. The buck-boost converter may refer to a buck-boost split phase circuit structure capable of performing a buck-boost method. Here, the buck-boost method may be a technique for DC-DC power conversion that increases (boost mode) or decreases (buck mode) an input voltage.

502 The processoraccording to an embodiment may generate a pulse width modulation (PWM) signal that controls the on/off of the first switch and the second switch. The PWM signal may be a DC voltage signal in the form of a pulse and may operate with a certain duty ratio.

502 502 At this time, the processormay generate different PWM signals by adjusting the width of the pulse. The processormay adjust the width of the pulse by adjusting the duty ratio of the pulse. At this time, a duty ratio may mean a ratio of time that a signal is on at a certain frequency.

A PWM signal having a constant frequency may have a repetitive on/off state, thereby controlling the on/off of the first switch and the second switch. At this time, the PWM signals respectively applied to the first switch and the second switch may be different from each other.

500 502 5 10 FIGS.to A detailed description of various operations of the devicethat may be performed by the processorwill be described below with reference to.

502 The processormay be implemented by using at least one of application-specific integrated circuits (ASICs), DSPs, digital signal processing devices (DSPDs), programmable logic devices (PLDs), FPGAs, controllers, micro-controllers, microprocessors, and other electrical units for performing functions.

503 503 10 503 16 1 FIG. The power conversion moduleis a component that performs conversion between DC power (voltage) and alternating current (AC) power (voltage), and may perform conversion for an input voltage, etc. For example, the power conversion modulemay convert DC link power received from a power plant, etc. into AC power. The power supply systemdescribed above with reference tomay transmit an output voltage generated as a result of the operation of the power conversion moduleto the external power grid.

503 The power conversion modulemay include a circuit board that provides a support base for internal configurations provided within the power conversion module, and various circuit elements disposed on the circuit board. The circuit board may provide a support base for internal configurations including components and various circuit elements provided within a power conversion module.

The circuit elements disposed on the circuit board may include either passive components, such as resistors, inductors, and capacitors, or active components, such as transistors and diodes.

503 For example, the power conversion modulemay include an input circuit, an output circuit, the first full-bridge inverter, and the second full-bridge inverter. The input circuit may be a circuit that obtains an input voltage. The output circuit may be a circuit that obtains an output voltage. Here, the input voltage may be a voltage input as DC, and the output voltage may be an AC output voltage output as AC.

503 5 7 FIGS.to Examples of the input circuit, the output circuit, the first full-bridge inverter, and the second full-bridge inverter included in the power conversion moduleare specifically described with reference to.

5 FIG. is an example of a circuit diagram of a first full-bridge inverter configuring a power conversion apparatus according to an embodiment.

630 630 630 According to an embodiment, the first full-bridge inverter may include two legs connected in parallel to an input circuit. For example, the two legs may include a first legand a second leg. At this time, the first legand the second leg may be formed in the same structure. Accordingly, the first legis mainly described below.

630 610 620 60 The first legmay include two switchesand. That is, the first full-bridge inverter may be a circuitimplemented as a full-bridge inverter including four switches.

500 610 620 630 500 610 620 The devicemay control, based on a first carrier signal applied to one of the legs, the on/off of the two switchesandincluded in the corresponding leg. The devicemay control the on/off of the two switchesandbased on the difference between the first carrier signal and a reference signal, which are applied to one of the legs.

640 640 640 630 The first full-bridge inverter may be connected to a first inductor. The first inductormay be connected to at least one of the two legs included in the first full-bridge inverter. That is, two first inductorsmay be respectively connected to the first legand the second leg of the first full-bridge inverter.

640 610 620 630 640 610 620 630 610 620 The first inductormay be connected between the two switchesandincluded in the first leg. The first inductormay be connected to the center of an upper switchand a lower switch, which are included in the first leg. At this time, the upper switchmay be connected to a (+) positive terminal of DC power supply of the input circuit. The lower switchmay be connected to a (−) negative terminal of DC power supply of the input circuit or to ground.

630 60 According to an embodiment, the second full-bridge inverter may have the same structure as the first full-bridge inverter. That is, the second full-bridge inverter may include two legsconnected in parallel to the input circuit. That is, the second full-bridge inverter may be a circuitimplemented as a full-bridge inverter including four switches.

The second full-bridge inverter may be connected to a second inductor. The second inductor may be connected to at least one of the two legs included in the second full-bridge inverter. That is, the second full-bridge inverter may be connected to two second inductors respectively connected to the two legs.

640 640 640 500 The first inductorand the second inductor may each be connected to the output circuit that generates an output voltage. The first inductorand the second inductor may perform LC filter functions for outputs of respective legs. The first inductorand the second inductor may perform smoothing of output currents of respective legs and suppress noise generated during a rapid switching process. Accordingly, the devicemay stably generate an AC output voltage.

6 FIG. In other words, the first full-bridge inverter and the second full-bridge inverter may include the same circuit structure as a single phase bipolar inverter. A method by which the plurality of switches included in each of the first full-bridge inverter and the second full-bridge inverter operate is described below in.

6 FIG. is an example circuit diagram of an interleaved bipolar inverter configuring a power conversion apparatus according to an embodiment.

500 710 730 740 710 735 736 730 745 746 740 720 735 736 745 746 The deviceaccording to an embodiment may include an input circuitgenerating an input voltage, a first full-bridge inverterand a second full-bridge inverter, which are connected to the input circuit, at least one first inductorandconnected to the first full-bridge inverter, at least one second inductorandconnected to the second full-bridge inverter, and an output circuitconnected to the at least one first inductorandand the at least one second inductorandto generate an AC output voltage.

500 751 735 736 752 745 746 751 752 At this time, the devicemay include a capacitorconnected to the at least one first inductorandand a capacitorconnected to the at least one second inductorand. The capacitorsandmay perform charging/discharging to alleviate voltage changes that occur during a switching operation.

751 735 736 735 736 751 752 745 746 For example, the capacitormay perform charging to store charge in case that a voltage transmitted through the at least one first inductorandincreases rapidly. In case that a voltage transmitted through the at least one first inductoranddecreases rapidly, the capacitormay perform discharge to release the stored charge. This may be performed similarly for the capacitorand the at least one second inductorand. Accordingly, an output voltage ripple may be eliminated and an output voltage may be stabilized.

500 730 740 731 732 733 734 730 741 742 743 744 740 The deviceaccording to an embodiment may include at least one processor that applies a first carrier signal and a reference signal to the first full-bridge inverterand applies a second carrier signal and the reference signal to the second full-bridge inverter. Based on the first carrier signal and the reference signal, a plurality of switches,,, andincluded in the first full-bridge invertermay operate. Based on the second carrier signal and the reference signal, a plurality of switches,, andincluded in the second full-bridge invertermay operate.

730 740 710 730 740 According to an embodiment, the first full-bridge inverterand the second full-bridge invertermay be connected in parallel to the input circuit. As the reference signal, the first carrier signal, and the second carrier signal are applied, the first full-bridge inverterand the second full-bridge inverter, which are connected in parallel, may operate in an interleaved manner.

730 735 736 740 745 746 8 9 FIGS.and That is, one bipolar inverter including the first full-bridge inverterand the at least one first inductorandmay operate, and the remaining one bipolar inverter including the second full-bridge inverterand the at least one second inductorandmay operate. At this time, two bipolar inverters may operate in an interleaved manner. A specific process of applying the reference signal, the first carrier signal, and the second carrier signal and a method of performing an interleaved operation accordingly will be described below with reference to.

7 FIG. is an example circuit diagram of an interleaved bipolar inverter applying a buck-boost technique according to an embodiment.

500 811 812 710 820 811 812 500 851 811 820 852 812 820 According to an embodiment, the devicemay include a first switchand a second switch, which are connected to the input circuit, and a third inductorconnected to the first switchand the second switch. In some embodiments, the devicemay further include a first capacitorconnected to the first switchand the third inductor, and a second capacitorconnected to the second switchand the third inductor.

811 710 811 812 710 812 Here, the first switchmay be connected to the positive electrode part of the input voltage source. For example, the first switchmay be connected to the positive electrode (+) of a DC link. The second switchmay be connected to a negative electrode part of the input voltage source included in the input circuit. For example, the second switchmay be connected to the negative electrode (−) of the DC link.

811 812 820 851 852 840 840 840 851 852 The first switch, the second switch, the third inductor, the first capacitor, and the second capacitormay be components configuring a buck-boost split phase circuit. Components configuring the buck-boost split phase circuit may form a buck-boost converter. The buck-boost convertermay mean a functional structure that is connected to a DC link to output a certain DC voltage. The buck-boost convertermay mean a functional structure configured to control a certain DC voltage to be output based on the voltage difference between the first capacitorand the second capacitor. At this time, the output certain DC voltage may be a voltage split from a DC link voltage.

811 812 820 830 830 According to an embodiment, the first switch, the second switch, and the third inductormay be connected to a neutral pointnode. The neutral pointmay mean a reference point that may split a voltage between the positive and negative electrodes of the DC link and provide a symmetrical voltage.

830 830 851 852 820 7 FIG. The neutral pointmay mean a point corresponding to the center of a three-phase system. The neutral pointmay be the center of a Y-connection circuit to which the first capacitor, the second capacitor, and the third inductorare connected, as shown in.

502 830 502 851 852 According to an embodiment, at least one processormay perform voltage control relative to the neutral pointnode. The processormay perform control based on the voltage difference between the first capacitorand the second capacitor.

502 811 812 820 502 811 812 851 852 502 851 852 In some embodiments, the processormay generate a PWM signal that controls the on/off of the first switchand the second switch, which are connected to the third inductor. At this time, the at least one processormay control the first switchand the second switchbased on the voltage difference between the first capacitorand the second capacitor. That is, the PWM signal generated by the processormay be a voltage signal that causes the difference in voltage across each of the first capacitorand the second capacitorto become 0.

502 The at least one processormay use a certain control algorithm to calculate a signal required for control and generate a PWM signal. The certain control algorithm may be an algorithm that generates a signal required for compensation based on a measured voltage difference value. The certain control algorithm may be, for example, a proportional-integral (PI) control algorithm or a support vector machine (SVM) algorithm, but is not limited thereto.

811 812 811 811 812 812 The generated PWM signal may include both a first PWM signal applied to the first switchand a second PWM signal applied to the second switch. In case that the first PWM signal is applied to the first switch, the on/off of the first switchmay be controlled. At the same time, in case that the second PWM signal is applied to the second switch, the on/off of the second switchmay be controlled.

851 851 852 At this time, each generated PWM signal may have a certain duty ratio. In case that the duty ratio of the first PWM signal increases, the voltage of an output end connected to the first capacitormay increase. A certain duty ratio may be determined by considering the capacitance of the first capacitorand the second capacitor.

851 852 502 851 852 851 852 For example, in case that the capacitance of the first capacitoris equal to the capacitance of the second capacitor, the processormay generate PWM signals by setting the duty ratio of each PWM signal to a value close to 50%. As another example, in case that the capacitance of the first capacitoris different from the capacitance of the second capacitor, the ratios of respective voltages applied to the first capacitorand the second capacitormay be proportional to respective capacitances.

502 820 502 820 The processormay generate a first PWM signal and a second PWM signal to control current flowing in the third inductor. The processormay control the current flowing in the third inductorby adjusting the duty ratios of the first PWM signal and the second PWM signal and applying the signals to respective switches.

851 852 502 851 852 For example, in case that a voltage across the first capacitoris higher than a voltage across the second capacitor, the processormay perform a control operation to increase a voltage of a node positioned between the first capacitorand the second capacitor.

502 811 811 502 812 To this end, the processormay adjust the duty cycle of the first PWM signal applied to the first switchto increase the duty ratio of the first switch. The processormay relatively reduce the duty ratio of the second switchby adjusting the duty cycle of the second PWM signal.

811 811 811 830 851 852 820 In case that the duty ratio of the first switchincreases, the time for which the first switchis maintained in an ON state may increase. In case that the time for which the first switchis maintained in the ON state increases, the voltage of the neutral pointnode may approach the positive electrode of the DC link. In this case, the current flowing in a direction of the first capacitorand the second capacitorfrom the third inductormay increase.

851 852 820 851 852 502 851 852 That is, charge is replenished toward the direction of the first capacitorand the second capacitorfrom the third inductor, and accordingly, the voltage of the node positioned between the first capacitorand the second capacitormay increase. Accordingly, the processormay control the difference in voltage across each of the first capacitorand the second capacitorto approach 0.

502 851 852 That is, the processormay maintain the voltage evenly by controlling the difference in voltage across each of the first capacitorand the second capacitorto be maintained at 0. As a result, an input voltage may be split into two symmetrical voltages. In other words, a symmetrical voltage of a split phase may be generated.

830 For example, the neutral pointvoltage may be maintained at a value corresponding to the middle of the voltage between the positive and negative electrodes of each DC link. The symmetrical voltage of the split phase may be applied to an input end of an inverter. That is, the symmetrical voltage may be applied to an input end of each of a first full-bridge inverter and a second full-bridge inverter, which are connected in parallel.

502 830 0 502 830 851 852 According to another embodiment, the processormay further perform current control so that the sum of currents based on the neutral pointbecomes. The processormay measure the sum of currents at the neutral pointnode in case a difference in voltage across each of the first capacitorand the second capacitoroccurs.

502 735 736 745 746 820 502 811 812 In some embodiments, the processormay measure current flowing through each of the at least one first inductorand, the at least one second inductorand, and the third inductor. In case that the sum of currents is not 0, the processormay control the first switchand the second switchto make the sum of the currents to become 0.

502 811 812 502 The processormay generate a first PWM signal and a second PWM signal, which generate a compensation current, so that the sum of the currents becomes 0. The generated first PWM signal and second PWM signal may be applied to the first switchand the second switch, respectively. Accordingly, the processormay simultaneously perform voltage control and current control to generate a stable symmetrical voltage.

500 830 500 500 500 In this way, the devicemay divide a single-phase voltage based on the neutral point. In some embodiments, the devicemay stably maintain a phase split voltage even when a load environment changes. For example, the devicemay supply a voltage of DC 240 V into a voltage of AC 120 V. Accordingly, the devicemay supply two symmetrical AC 120 V voltages from one DC 240 V voltage source.

811 812 820 70 6 FIG. An operation of controlling the first switch, the second switch, and the third inductorand an operation of controlling the interleaved bipolar inverterdescribed above with reference todo not affect each other.

8 FIG. is an example of a method by which each switch included in a power conversion apparatus according to an embodiment operates.

8 FIG. 502 1 2 Referring to, as an example, the processormay apply a control signal in the form of a sine wave and a first carrier signal Carand a second carrier signal Car, which are in the forms of square waves.

502 1 502 1 731 732 500 731 732 733 734 According to an embodiment, the processormay apply the first carrier signal Carto any one of the legs included in the first full-bridge inverter. For example, the processormay apply the first carrier signal Carto a leg including switchesand. Accordingly, the devicemay control the on/off of the switches,,, andincluded in the first full-bridge inverter.

1 502 1 According to an embodiment, the first full-bridge inverter may operate based on the difference between the first carrier signal Carand a reference signal Ma. The processormay turn on specific switches included in the first full-bridge inverter depending on whether the difference between the first carrier signal Carand the reference signal Ma is a positive value.

1 2 1 731 732 2 3 1 731 732 For example, between time tand time t, the first carrier signal Carmay have a value less than the reference signal Ma. At this time, an upper switchmay be turned on and a lower switchmay be turned off. For example, between time tand time t, the first carrier signal Carmay have a value greater than the reference signal Ma. At this time, the upper switchmay be turned off and the lower switchmay be turned on.

731 734 732 733 731 734 732 733 At this time, the upper switchand an opposite switchmay perform the same on/off operation. For example, the lower switchand an opposite switchmay perform the same on/off operation. That is, a certain switch pairandand another switch pairandcan operate complementarily with each other.

1 1 731 734 1 1 1 1 732 733 1 In case that the first carrier signal Carand the reference signal Ma are applied, an on/off waveform Dutyof the certain switch pairandmay be output. At this time, the on/off waveform Dutymay be determined according to a waveform of each of the first carrier signal Carand the reference signal Ma. That is, the duty cycle of the on/off waveform Dutymay be determined according to a cycle of each of the first carrier signal Carand the reference signal Ma. For example, the on/off waveform (not shown) of another switch pairandmay have a complementary form to the on/off waveform Duty.

502 2 502 2 741 742 500 741 742 743 744 According to an embodiment, the processormay apply the second carrier signal Carto one of the legs included in the second full-bridge inverter. For example, the processormay apply the second carrier signal Carto a leg including switchesand. Accordingly, the devicemay control the on/off of the switches,,, andincluded in the second full-bridge inverter.

2 502 2 In an embodiment, the second full-bridge inverter may operate based on the difference between the second carrier signal Carand the reference signal Ma. The processormay turn on specific switches included in the second full-bridge inverter depending on whether the difference between the second carrier signal Carand the reference signal Ma is a positive value.

4 5 2 741 742 5 6 2 741 742 For example, between time tand time t, the second carrier signal Carmay have a value greater than the reference signal Ma. At this time, an upper switchmay be turned off and a lower switchmay be turned on. For example, between time tand time t, the second carrier signal Carmay have a value smaller than the reference signal Ma. At this time, the upper switchmay be turned on and the lower switchcan be turned off.

741 744 742 743 741 744 742 743 At this time, the upper switchand an opposite switchmay perform the same on/off operation. Meanwhile, the lower switchand an opposite switchmay perform the same on/off operation. That is, a certain switch pairandand another switch pairandmay operate complementarily with each other.

2 2 741 744 2 2 2 2 742 743 2 As the second carrier signal Carand the reference signal Ma are applied, an on/off waveform Dutyof the certain switch pairandmay be output. At this time, the on/off waveform Dutymay be determined according to a waveform of each of the second carrier signal Carand the reference signal Ma. That is, the duty cycle of the on/off waveform Dutymay be determined according to a cycle of each of the second carrier signal Carand the reference signal Ma. For example, the on/off waveform (not shown) of another switch pairandmay have a complementary form to the on/off waveform Duty.

1 2 1 2 According to an embodiment, the first carrier signal Carmay have the same switching cycle as the second carrier signal Car. A switching cycle may refer to a cycle of a voltage signal for controlling each switch. In some embodiments, the first carrier signal Carmay have a certain phase difference from the second carrier signal Car. The certain phase difference may be, for example, half a cycle (180°).

Accordingly, the first full-bridge inverter and the second full-bridge inverter may respectively operate based on the first carrier signal and the second carrier signal, which are waveforms of the same cycle with a certain phase difference. At this time, the first full-bridge inverter to which the first carrier signal is applied and the second full-bridge inverter to which the second carrier signal is applied may operate with a certain time difference. That is, the first full-bridge inverter and the second full-bridge inverter may operate in an interleaved manner.

9 FIG. is an example of a grid current Ig waveform of a power conversion apparatus according to an embodiment.

9 FIG. 1 731 734 2 741 744 Referring to, the cycle of each of the on/off waveform Dutyof the certain switch pairandincluded in the first full-bridge inverter and the on/off waveform Dutyof the certain switch pairandincluded in the second full-bridge inverter may be checked. For example, the cycle of the grid current Ig waveform may be checked.

1 731 734 731 734 1 1 1 For example, between time ta and time tc, it may be checked from Dutythat the switch pairandremains in the on state. In this case, as the current through the switch pairandincreases, an output current Imay show an increasing pattern. At this time, the cycle of the output current Iwaveform may match the cycle of Duty.

2 741 744 2 741 744 2 741 744 2 2 2 It may be checked from Dutythat, between time ta and time tb, the switch pairandremains in the off state. In this case, an output current Imay not exist as the flow through the switch pairandis interrupted. Conversely, between time tb and time tc, it may be checked from Dutythat the switch pairandremains in the on state. In this case, the output current Iincreases again. At this time, the cycle of the output current Iwaveform may match the cycle of Duty.

1 1 2 2 1 2 1 2 1 2 Dutymay appear based on the first carrier signal Car, and Dutymay appear based on the second carrier signal Car. The first carrier signal Carand the second carrier signal Carmay be waveforms of the same cycle with a certain phase difference. Accordingly, the cycle of Dutyand the cycle of Dutymay be the same with a certain phase difference, and thus, the cycle of the output current Iand the cycle of the output current Imay also be the same with a certain phase difference.

1 2 1 2 1 2 The grid current Ig may have a waveform in which the output current Iand the output current Iare superimposed. There is a constant phase difference between the output current Iand the output current I, and thus a ripple current occurring in respective outputs may be offset. The grid current Ig, in which the output current Iand the output current Iare superimposed, may have a waveform in which the ripple current is offset.

1 2 1 2 Here, the cycle of the grid current Ig waveform may correspond to half of the cycles of Dutyand Duty. Here, Dutymay represent an operation of each switch included in the first full-bridge inverter. Dutymay represent an operation of each switch included in the second full-bridge inverter. In other words, the frequency of the grid current Ig waveform may be twice an operating frequency of each switch included in the first full-bridge inverter or the second full-bridge inverter.

70 6 7 FIGS.and Accordingly, a peak-to-peak value Ip of the grid current Ig may be reduced compared to when using a single full-bridge inverter. That is, the interleaved bipolar inverterdescribed above with reference tomay reduce the total harmonic distortion (THD) of an AC output compared to when a single full-bridge inverter is used.

10 FIG. is a flowchart of a method by which a power conversion apparatus according to an embodiment operates.

10 FIG. 4 FIG. 4 FIG. 10 FIG. 500 500 500 The method illustrated inmay be operations performed in the deviceof. Accordingly, even if omitted below, the above-described contents related to the operation of the deviceand components of the deviceofmay also be applied to the method illustrated in.

1110 502 1120 502 According to an embodiment, in operation, the processormay apply a first carrier signal and a reference signal to the first full-bridge inverter. In operation, the processormay apply a second carrier signal and the reference signal to the second full-bridge inverter. At this time, the first full-bridge inverter and the second full-bridge inverter may be connected in parallel with the buck-boost converter. For example, the buck-boost converter may be connected to an input circuit.

1130 720 503 502 502 In operation, as the first full-bridge inverter and the second full-bridge inverter operate, the output circuitincluded in the power conversion modulemay obtain an AC output voltage corresponding to an input voltage. The first full-bridge inverter may operate according to the first carrier signal and the reference signal, which are applied by the processor. Similarly, the second full-bridge inverter may operate according to the second carrier signal and the reference signal, which are applied by the processor.

Here, the first full-bridge inverter may operate based on the difference between the first carrier signal and the reference signal, and the second full-bridge inverter may operate based on the difference between the second carrier signal and the reference signal.

The first carrier signal may have a certain phase difference from the second carrier signal. In some embodiments, the first carrier signal may have the same switching cycle as the second carrier signal.

502 The processormay control the on/off of two switches included in one of the legs based on the first carrier signal and the reference signal applied to the one leg. Here, each of the legs may include two switches, and the first full-bridge inverter may include two legs connected in parallel to the input circuit.

720 An AC output voltage may be generated in the output circuitconnected to at least one first inductor and at least one second inductor. The at least one first inductor may be connected to the first full-bridge inverter, and the at least one second inductor may be connected to the second full-bridge inverter.

502 The processormay control the first switch and the second switch based on the voltage difference between the first capacitor and the second capacitor. A plurality of current sensors may be respectively connected to the at least one first inductor, the at least one second inductor, a third inductor, and the third inductor may be connected to the first switch and the second switch, and the first switch and the second switch may be connected to the input circuit.

502 The processormay generate PWM signals that control on/off of the first switch and the second switch.

A computer-readable recording medium according to an embodiment may record a program for executing a method on a computer.

The embodiments according to the disclosure described above may be implemented in the form of a computer program that may be executed through various components on a computer, and such a computer program may be recorded on a computer-readable medium.

At this time, the medium may include magnetic media, such as hard disks, floppy disks, and magnetic tapes, optical recording media, such as CD-ROMs and digital versatile discs (DVDs), magneto-optical media, such as floptical disks, and hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, and flash memory.

The computer program may be specially designed and configured for the disclosure or may be known and available to those skilled in the art in the computer software field. Examples of computer programs may include not only machine language code, such as that produced by a compiler, but also high-level language code that may be executed by a computer by using an interpreter or the like.

According to the disclosure, a dual bipolar structure operating in an interleaved manner may be applied as the structure of a power conversion apparatus to reduce a load borne by each inverter, thereby reducing loss and heat generation due to THD.

For example, according to the disclosure, there is an advantage in that an output may be controlled more precisely through voltage and current control by additionally utilizing the phase division of a buck-boost technique applicable to the above interleaved bipolar inverter.

The specific implementations described in the disclosure are merely examples and do not limit the scope of the disclosure in any way. For the sake of brevity of the specification, descriptions of conventional electronic components, control systems, software, and other functional aspects of the systems may be omitted. For example, connection lines or connection members between components depicted in the drawings are merely illustrative of functional connections and/or physical or circuit connections, and may be represented as various functional connections, physical connections, or circuit connections that may be replaced or added in an actual device. For example, if there is no specific mention of an element such as “essential,” “important,” etc., it may not be an essential component for the application of the disclosure.

The use of the terms “above” and similar referent terms in the specification of the disclosure (especially in the claims) may refer to both the singular and the plural. For example, when a range is described in the disclosure, it is considered to include a disclosure that applies individual values belonging to the range (unless otherwise stated), and is the same as describing each individual value constituting the range in the detailed description of the disclosure.

Unless there is an explicit description or contradiction of the order of the operations configuring the method according to the disclosure, the operations may be performed in any suitable order. The disclosure is not necessarily limited to the order in which the above operations are described. The use of any examples or exemplary terms (e.g., “for example,” “etc.”) in the disclosure is merely intended to illustrate the disclosure in more detail and is not intended to limit the scope of the disclosure by reason of such examples or example terms, unless otherwise limited by the claims. Furthermore, those skilled in the art will appreciate that various modifications, combinations and variations may be made according to design conditions and factors within the scope of the appended claims or their equivalents.

Therefore, the idea of the disclosure should not be limited to the embodiments described above, and not only the scope of the patent claims described below but also all scopes equivalent to or equivalently modified from the scope of the patent claims are included in the scope of the idea of the disclosure.